Final answer:
The correct relationship is C, which states that as the average speed of a car increases, the time to drive from Denver to Chicago decreases, based on the calculation of average speed which is distance divided by time.
Step-by-step explanation:
The correct statement that expresses a possible relationship between the variables of travel time from Denver to Chicago and the average speed of a car is: C. As the average speed of a car increases, the time to drive from Denver to Chicago decreases.
This relationship is based on the equation for average speed, which is the distance traveled divided by the time of travel. For example, if a car travels 150 kilometers in 3.2 hours, its average speed (Vavg) would be calculated as:
Vavg = distance / time = 150 km / 3.2 h = 47 km/h.
Thus, the faster the average speed of the vehicle, the less time it will take to cover the same distance, assuming the distance between Denver and Chicago remains constant. This inverse relationship is key in understanding how speed affects travel time.